The prior art has included a number of ultrasonic catheters which are insertable into the mammalian body and usable to deliver ultrasonic energy for purposes of ablating obstructive material from anatomical cavities or passageways, or for other therapeutic purposes.
Examples of ultrasonic treatment catheters and related apparatus include those described in U.S. Pat. Nos. 3,433,226 (Boyd), 3,823,717 (Pohlman, et al.), 4,808,153 (Parisi), 4,936,281 (Stasz), 3,565,062 (Kuris), 4,924,863 (Sterzer), 4,870,953 (Don Michael, et al.), 4,920,954 (Alliger, et al.), 5,267,954 (Nita), as well as other patent publications WO87-05739 (Cooper), WO89-06515 (Bernstein, et al.), WO90-0130 (Sonic Needle Corp.), EP316789 (Don Michael, et al.), DE3,821,836 (Schubert) and DE2,438,648 (Pohlman).
Additionally, ultrasound transmitting catheters may be utilized to deliver ultrasonic energy to mammalian blood vessels for the purpose of preventing or reversing vasospasm, as described in U.S. Pat. No. 5,324,255.
The prior art has also included a number of atherectomy devices which are insertable into blood vessels and usable to cut, shave or otherwise sever obstructive matter from the walls of the blood vessel. Such atherectomy devices typically include aspiration channels for suctioning the severed matter from the lumen of the blood vessel. Examples of atherectomy devices which have heretofore been know include those described in U.S. Pat. No. 5,100,423 (Fearnot),
Additionally, U.S. Pat. No. 4,808,153 (Parisi) has described a device for removing placque from arteries wherein a hollow tip member is mounted on the distal end of a tubular catheter, and an ultrasound source is connected to the proximal end of the catheter to cause the entire catheter, including the distal tip, to undergo vibratory movement. Such vibratory movement of the hollow distal tip member ostensibly creates heat which serves to emulsify obstructive matter which is located on the walls of an artery adjacent the vibrating hollow tip member. The emulsified matter is subsequently suctioned or withdrawn, in the proximal direction, through the hollow tip member and through the lumen of the catheter.
Although the device described in U.S. Pat. No. 4,808,153 (Perisi) is purportedly useable to remove obstructive matter from the walls of a blood vessel, the device disclosed in such prior United States patent is believed to be of less than optimal design for all intravascular applications. Accordingly, there remains a need for a new ultrasonic angioplasty catheter capable of utilizing ultrasound-induced vibratory motion to sever or separate obstructive matter from the walls of blood vessels or other anatomical passageways, and which includes means for promptly removing the severed or separated matter from the lumen of the blood vessel or anatomical passageway.